Core Principles of the Red Queen Hypothesis

Several key ideas emerge from the RQH:

• Constant Extinction Rate (Statement A): Van Valen observed that the probability of extinction for taxa appears constant over time, regardless of their age. This “Law of Constant Extinction” suggests that species do not become more fit over time in a way that reduces their extinction risk, because the biotic environment they inhabit is always changing due to the evolution of other species.

• Perpetual Evolution (Statement B): Even without environmental changes, species must constantly adapt because the organisms they interact with are also evolving. This ongoing evolutionary change is necessary to maintain fitness relative to other species.

• Selective Advantage of Novel Genotypes (Contradicting Statement C): Contrary to the idea that organisms with novel genotypes are at a selective disadvantage, the RQH implies that genetic novelty can be advantageous. Continuous evolution requires generating new genetic variants to keep pace with co-evolving species.

• Maintenance of Genetic Variation Through Coevolution (Statement D): The hypothesis posits that coevolutionary interactions between species help maintain genetic diversity over time. This is because fluctuating selection pressures favor different genotypes at different times, preventing any single genotype from becoming fixed.

Which Statements Does the Red Queen Hypothesis Support?

Based on the above understanding:

• (A) Within a lineage, organisms show a constant rate of extinction: Supported by Van Valen’s Law of Constant Extinction.

• (B) Even in the absence of changing interactions, organisms are constantly evolving: Supported, as the RQH emphasizes ongoing evolution driven by biotic interactions.

• (C) Organisms with novel genotypes are at a selective disadvantage: Not supported; the hypothesis suggests novel genotypes can be favored to keep up in the evolutionary race.

• (D) Coevolution between two interacting species acts to maintain genetic variation through time: Supported, as coevolutionary dynamics promote genetic diversity.

Therefore, the combination of statements A and B best aligns with the Red Queen Hypothesis.

Conclusion

The Red Queen Hypothesis explains that species must continuously evolve due to persistent biotic interactions, leading to a constant extinction rate and perpetual evolutionary change. It also highlights the role of coevolution in maintaining genetic diversity. Among the given options, statements A and B are supported by the Red Queen Hypothesis.

Correct answer:
(2) A and B